Antenna



J. B. CEJKA May 27, 1958 ANTENNA 2 Sheets-Sheet 1 mmm Filed Nov. 20, 1953 FIG. I.

ll/"Illa I,Lllll INVENTOR (/OEP/v B. (Ed/(A @an ffm-f kai/w ATTORNEYS May 27, 1958 Filed Nov. 20, 1953 FlG.. 3.

J. B. CEJKA 2 Sheets-Sheet 2 FIG. 4.

lNvENToR (/OSEPH B. CEL/KA' United States Patent lO ANTENNA Joseph B. Cejka, Highland Park, N. J., assignor to General Bronze Corporation, Garden City, N. Y., a corporation of New York Application November 20, 1953, Serial No. 393,333

s claims. (ci. 1mi- 139)` This invention relates to improvements in whip-type automobile antennas and more particularly to a simplified construction providing improved electrical and mechanical characteristics.

With the increasing use of automobile radios, the cost and performance characteristics of automobile radio antennas have assumed increased importance. The present invention is directed to an improved arrangement within the base sleeve of the antenna which provides a 'better support for the telescoping tube and rod assembly, low shunt capacity, and a longer electrical leakage path between the signal-carrying portions and the grounded base sleeve, and which requires fewer parts and is less expensive to manufacture and assemble.

These and other aspects, advantages, and objects of the present invention will in part be apparent from and in part pointed out in the following description considered in conjunction with the accompanying drawings, in which:

Figure l is a cross-sectional view showing an automobile radio antenna embodying the present invention;

Figure 2 is an exploded view showing in perspective the parts ofthe antenna of Figure 1;

Figure 3 is an enlarged partial sectional view showing the arrangement and shape of certain of the insulating and mechanical supporting members within the sleeve base; and

Figure 4 is an enlarged sectional View of a retaining and connecting screw showing the position of a Phosphor bronze contact spring.

The signal receiving portion 2 of the antenna, in this example a telescoping tube and rod assembly, is supported by a sleeve base 4 that passes through and is secured to the sheet metal 6 which forms the cowl or other portion of an automobile body.

The lowermost member, in this example a length of tubing 8, extends into the sleeve 4 and provides support for the other parts of the signal-receiving portion and serves also to conduct the received signals through the sleeve 4 to a connector plug 10 which is positioned in the lower end of the sleeve 4 and is connected by a shielded cable 12 to the radio receiver (not shown),

In order to insulate the tubing 8 from the sleeve 4, which is electrically connected to the metal body of the automobile, a tubular insulating bushing 14 is positioned around the lower end of the tubing 8 within the sleeve 4. In this example, the insulating bushing 14 is molded of polystyrene, although any other insulating material hav ing similar electrical properties and requisite mechanical strength and flexibility can 'be used.

The tube S is anchored in the insulating bushing 14 by a screvtl 16 (Figure 3) which is in threaded engagement with the interior of the tube S and draws the lower end of the tube downwardly against an internal annular shoulder of the bushing 14, as shown at 18. The head of the screw 16 is drawn upwardly against a washer 20 which is supported by a lower internal annular shoulder surface of the bushing 14 as indicated at 22.

rwice In order to secure the bushing 14 into the sleeve 4, an external annular shoulder near the lower end of the bushing 14 is arranged to abut a corresponding annular shoulder, as at 24, on the inner wall of the sleeve 4. The upper end of the bushing 14 is anchored after it is inserted in the sleeve 4 by rolling or swaging the upper end of the sleeve 4 inwardly, as at 26, against a sloping annular shoulder 28 (Figure 2) on the ouside of the bushing 14 so that the bushing is' rmly anchored between the lower shoulder 24 and the internal collar thus formed at the upper end of the sleeve 4. The insula-4 tion 'bushing is selected to fit nicely over the tube 8 and is suiciently resiilent that the rolling or swaging action at the upper end of the sleeve 4 forms effective water tight seals between the sleeve 4 and the bushing 14 and between the bushing 14 and the tube 8.

The threads byY which the screw 16 engages the tube 8 are formed in a section of the tube that has been rolled to a slightly smaller diameter, as shown at 30 in Figure 2, than the remainder of the tube. This assures accurate dimensions and full threads irrespective of slight variations in size of the tubing used in the antenna. This section of the tubing which is of reduced diameter is spaced from the lower end of the tube 8 so as to provide an increased anchoring effect within the fbushing 14 and so that the lower end of the tube 8 will have maximum diameter adjacent the shoulder 18.

In order to make electrical connection between the tube 8 and the contact prong 32 of the plug 10, a longitudinal bore 34 is provided through the screw 16 to receive the prong 32 when the plug is inserted through the lower end of the sleeve 4. In order to insurea` good noiseafree contact between the prong 32 and the screw lo, a strip` 3o of Phosphor bronze spring metal is positioned within the 'bore 34. This strip of material is spot welded or otherwise secured at its lower end -to the head of the screw 16 and extends upwardly through the bore 34, as best shown in Figure 4. Preferably the spring` is pre-shaped with one or more undulations along its length so as to further insure good contact with the central conductor prong 32.

The ground connection between a spring metal sleeve 38 on the plug 10 and the sleeve is completed by direct contact between the plug sleeve 38 and the inner wall of the sleeve 4.

In order to increase the length of the surface leakage path between the head of the screw 16 and the metal sleeve 4, a downwardly extending flange 40 is formed 0n the lower end of the bushing 14. The outer surface of this annular extension is tapered inwardly as shown in the enlarged partial view of Figure 3. Thus, a small space, as at 42, exists between the outer surface of the ange 40 and the inner wall of the sleeve 4. The long surface leakage path thus formed between the head of the screw 16 and the sleeve 4 markedly reduces the decrease in signal strength in the event of condensation on the surfaces.

The antenna sleeve 4 may be secured to the body 6 by any suitable means. In the illustrated embodiment a pair of elongated arms 44 are swingably secured respectively to opposite sides of the sleeve 4. To install the antenna these arms 44 are turned so as to extend parallel with the longitudinal axis of the sleeve and passed through a suitable opening in the auto body. The arms are then permitted to turn crosswise of the sleeve 4 so as to serve as an internal anchor when the antenna is secured in position by tightening an external nut 46 which is threaded onto the sleeve 4. This mounting arrangement is described more fully and is claimed in my copending application, Serial No. 393,331, tiled on even date herewith.

In order to provide a weather-tight seal around the antenna where it passes inside the automobile and to permit adjustment of the angle of the antenna relatively to the adjacent surface of the body, a soft rubber washer 48 is positioned around the sleeve 4 against the car body 6 and receives in an outer annular groove the lower surface of a slotted generally semi-spherical plastic insulator 50. A metal cup-shaped washer 52 is positioned on the insulator and extends over the slot in the insulator to form a water tight seal. When the antenna has been adjusted to the desired angle, the nut 46 is tightened to secure the antenna in position.

The assembly of the washer 48, insulator 50, washer 52, and nut 46 are conventional and may be the same as those already in wide use, these parts in themselves forming no part of the present invention.

What is claimed is:

1. A radio antenna for use on an automobile, comprising a telescoping tube and rod signal receiving assembly, an insulating bushing surrounding the lowermost section of said signal receiving assembly and having an internal upwardly facing annular shoulder against which the lower end of said lowermost section bears, a metal sleeve secured to and surrounding said insulating bushing, said sleeve being adapted to extend through an opening in an automobile body and having means for attachment of said antenna to said body, a screw member threaded into the lower end of said lowermost section and having a head portion engaging a downwardly facing annular shoulder on said bushing to secure said signal receiving member to said bushing, said screw member having an axial bore for receiving a plug for making electrical connection to said signal receiving member.

, 2.`A radio antenna for use on an automobile comprising a telescoping tube and rod signal receiving assembly, an insulating bushing surrounding the lowermost section of said signal receiving assembly and having an internal upwardly vfacing annular shoulder against which the lower end of said lowermost section bears, a metal sleeve secured to and surrounding said insulating bushing, said sleeve being adapted to extend through an opening in an automobile body and having means for attachment of said antenna to said body, a screw member threaded into the lower end of said lowermost section and having a head portion engaging a downwardly facing annular shoulder on said bushing to secure said signal receiving member to said bushing, said screw member having an axial bore for receiving a plug for makingelectrical connection to said signal receiving member, and said bushing having a downwardly depending annular ilange around the headed portion of said screw member, the outer surface of said flange being spaced from the inner surface of said sleeve.

3. A radio antenna for use on an automobile, comprising a telescoping tube and rod signal receiving assembly, a bushing of resilient insulating material surrounding the lowermost section of said signal receiving assembly and having an internal upwardly facing annular shoulder against which the lower end of said lowermost section bears, a malleable metal sleeve surrounding said bushing, said sleeve being adapted to extend through an opening in an automobile body and having means for attachment of said antenna to said body, an internal upwardly facing shoulder in said sleeve 'and an external downwardly facing annular shoulder on said bushing bearing against the same to limit downward movement of said bushing relative to said sleeve, an external upwardly facing annular shoulder near the upper end of said bushing, the upper end of said sleeve being swaged inwardly to exert pressure on the latter said shoulder to resist upward movement of said bushing relative to said sleeve and to form a water-tight seal between said sleeve and said bushing and between said bushing and said lowermost section, a screw member threaded into the lower end of said lowermost section and having a head portion engaging a downwardly facing annular shoulder on said bushing to'secure said signal receiving member to said bushing, said screw member having an axial bore for receiving a plug for making electrical connection to said signal receiving member.

References Cited in the file of this patent UNITED STATES PATENTS 2,509,563 Grashow May 30, 1950 2,536,053 Grashow Ian. 2, 1951 2,603,682 Uline et al July 15, 1952 2,617,933 Noel Nov. l1, 1952 

